Don't get a big head

Q:What's wrong with the old sci-fi notion that in1,000,000 years we humans will have big heads (brains), spindly limbs (disuse), bald pates (in progress), and no wisdom teeth or little toes (vestigial)?—Strange looking guy

A: It's hard to see what reproductive benefits thesewould confer, and if no benefits, no dice from an evolutionary standpoint, says Michael Onken of the MAD Scientist Network. A bigger head could even force a wider pelvis for birth, and throw off walking.Besides, even if someone gained survival advantage from being big-headed, hairless, and eight-toed, who would marry him? Mate selection has had profound effects, even in just the last century. But the real wild card in all this– and may apply in more like 1,000 years than 1,000,000– is genomic tinkering, says University of Hawaii anthropologist Daniel Brown. It may become possible to modify the human lifespan, intelligence, body shape–according to fads!At this point, natural selection and evolution are too slow and become irrelevant. Then some groups could even be altered to adapt to conditions on other planets, with space colonies and infrequent contact leading to speciation and new hominid forms. "Any sci-fi writers out there?"

Q:Given what recently happened in Georgia, how could you be sure the ashes you're given are the right ones of your loved one? How could you even tell if they constitute human remains?—Burned up

A: You ordinarily can't tell, and legal disputes arebecoming increasingly common along with more cremations today, say University of Florida forensic anthropologists Michael Warren and Tony Falsetti. Cremation destroys all DNA, so genetic "fingerprinting" of cremains won't work.One family suspected the brownish-white bone fragments it received were not authentic, and turned to the experts for help. The anthropologists echoed the doubts. Traditional cremations leave recognizable human bone fragments, but it's harder to tell with newer technologies that turn bone to a sand-like fine powder.Enter the physicists with their particle accelerators for ferreting out trace elements, which did find the calcium of human bone but no phosphorus, which should have been present. "We think it's a mixture of sandy soil with a little lime rock," said physicist Gene Dunnam. "Whoever did this was not entirely stupid, because lime rock contains calcium, which is also in bone."The technique can also tag trace barium (recent medical tests for the deceased?) or metals (any implants?), giving new meaning to "It's element-ary, my dear Watson."

Q: How often are twins born on different days, straddling the midnight hour to claim different birthdays?—Mom of multiples

A: The doctors won't exactly encourage this, since the majority of twin births are by cesarian and not likely to be midnight specials, says Lawrence Devoe, Medical College of Georgia obstetrician and gynecologist.Typical twin-delivery intervals whether for cesarian or vaginal are no more than 30 minutes. Still, given 70,000 to 80,000 twin pairs born annually in a nation the size of the United States, averaging 10 per hour, that's plenty of opportunity for stutter-celebrations. Except that the delivery times are far from random, says Devoe, so you wind up with an estimate of only maybe one back-to-backer occurring per week nationwide.Of course, back-to-back is not the whole story either, since there are cases where one twin is born premature and the other is delayed for days or even weeks, adds the University of North Carolina's Nancy Chescheir. Might have to put cake #2 (#3? #4?) in the deep freeze.